Hydration strategies of runners in the London Marathon.

Abstract

OBJECTIVE:

To explore the hydration strategies of marathon runners, their sources of information and knowledge about fluid intake in the marathon, and their understanding of exercise-associated hyponatremia (EAH).

DESIGN:

Anonymized questionnaire.

SETTING:

London Marathon.

PARTICIPANTS:

Marathon race participants.

MAIN OUTCOME MEASURES:

Responses regarding planned fluid consumption, volume to be consumed, volume of water and sports drink bottles, and the number of stations from which planning to take a drink. In addition, sources of information about appropriate drinking and understanding of hyponatremia.

RESULTS:

In total, 93.1% of the runners had read or been told about drinking fluids on marathon day and 95.8% of competitors had a plan regarding fluid intake. However, 12% planned to drink a volume large enough to put them at higher risk of EAH. Only 21.7% knew the volumes of water and sports drink bottles available on the course; 20.7% were planning to take a drink from all 24 water stations. Only 25.3% planned to drink according to thirst. Although 68.0% of the runners had heard of hyponatremia or low sodium levels, only 35.5% had a basic understanding of its cause and effects.